Staticcheck 2017.2 Release Notes

Introduction to staticcheck 2017.2

The 2017.2 release of the staticcheck suite of tools focuses on
reducing friction – fewer false positives, more tools for suppressing
unwanted output, and JSON output for easier integration with other
tools.

New features

Linter directives for ignoring problems

In the past, the only ways to ignore reported problems was by using
the -ignore flag. This led to overreaching ignore rules
which weren't maintained regularly. Now, //lint:ignore and
//lint:file-ignore comments can be used to ignore
problems, either on specific lines or file-wide. A full description of
these directives, their syntax and their behavior can be found
in the documentation.

A related change adds the -show-ignored command line
flag, which outputs problems that would otherwise be ignored by
directives. This is primarily of use with the JSON output format,
for custom front ends.

Output formats

All staticcheck tools now support multiple output formats, selectable
with the -f flag.

Currently, two formats are supported. The first format is
text, which is the default and uses the existing terminal
output format. The other is json, which emits JSON. The
output is a stream of objects, allowing for a future streaming output
mode. Each object uses the following example schema:

Control over the exit code of megacheck

Megacheck, the tool for running multiple checkers at once, now has
per checker flags for controlling the overall exit code. Previously,
megacheck would exit non-zero if any checker found a problem. Now it
is possible to configure for each checker whether it should cause a
non-zero exit, by using the -<checker>.exit-non-zero
flags. This flag defaults to false for gosimple and to true for
the other checkers.

Changes to checks

Support for NoCopy in unused

The unused tool now understands NoCopy sentinel types. The
NoCopy type, which is canonically a struct with no fields and only a
single, empty Lock method, can be used to mark structs as not safe
for copying. By declaring a field of this type, go vet will complain
when it sees instances of the struct being copied.

In the past, unused marked these fields as unused, now it ignores
them.

Detection of deprecated identifiers

SA1019 now
correctly identifies deprecated methods, in addition to fields and
package-level objects. Additionally, staticcheck now keeps track of
when each identifier in the Go standard library was deprecated, so
that using -go <version> can correctly
ignore deprecation warnings that don't apply to the targeted Go
version.

Other

SA4017 no
longer reports pure functions that are stubs – functions that
immediately panic or return a constant.

SA5007 no
longer flags infinite recursion when the function call is spawned
as a new goroutine.

S1005
no longer suggests for range when targeting a version
older than Go 1.4.

S1026 has been
removed. In some rare instances, copying a string is necessary, and
all common ways of doing this were incorrectly flagged by the check.

Other changes

The -ignore flag now supports ignoring checks in all packages,
by using * as the path.

//line directives are now being ignored when
reporting problems. That is, problems will always be reported for
the actual position in the Go files they occur.

From now on, only the first compilation error encountered will be
reported. The tools expect to be run on valid Go code and there
was little (if any) value in reporting all compilation errors
encountered, especially because simple errors can lead to many
follow-up errors.

Staticcheck 2017.2.1 Release Notes

The 2017.2.1 release of the staticcheck suite of tools is the first
bug fix release, fixing one bug.

Fixed bugs

Staticcheck 2017.2 made the detection of deprecated objects
Go-version aware. Unfortunately, this only worked correctly for
fields and methods, but not package-level objects. This release
fixes that.

Staticcheck 2017.2.2 Release Notes

The 2017.2.2 release of the staticcheck suite of tools is the second
bug fix release, fixing several bugs.

Fixed bugs

unused: correctly apply the NoCopy exemption when using the -exported flag.

keyify: support external test packages (package foo_test)

staticcheck: disable SA4005 – the check, in its current form, is prone to false positives and will be reimplemented in a future release.